Mitochondrial DNA is a widely tested genetic marker in various fields of research and diagnostics. Nonetheless, there is still little understanding on its abundance and quality within different tissues.

Aiming to obtain deeper knowledge about the content and quality of mtDNA, we investigated nine tissues including blood, bone, brain, hair (root and shaft), cardiac muscle, liver, lung, skeletal muscle, and buccal mucosa of 32 deceased individuals using two real-time quantitative PCR-based assays with differently sized mtDNA and nDNA targets.

The results revealed that the quantity of nDNA is a weak surrogate to estimate mtDNA quantities among tissues of an individual, as well as tissues across individuals. Especially hair showed extreme variation, depicting a range of multiple magnitudes of mtDNA molecules per hair fragment. Furthermore, degradation can lead to fewer fragments being available for PCR. The results call for parallel determination of the quantity and quality of mtDNA prior to downstream genotyping assays.

线粒体 DNA 是在各个研究和诊断领域中广泛测试的遗传标记。尽管如此，对其在不同组织中的丰度和质量仍然知之甚少。

为了更深入地了解 mtDNA 的含量和质量，我们使用两种方法对 32 名死者的血液、骨骼、大脑、头发（根和轴）、心肌、肝脏、肺、骨骼肌和颊粘膜等 9 种组织进行了研究。使用不同大小的 mtDNA 和 nDNA 靶标进行基于实时定量 PCR 的检测。

结果表明，nDNA 的数量是估算个体组织以及个体组织中 mtDNA 数量的弱替代指标。尤其是头发表现出极大的变异，每个头发片段都呈现出一系列多个数量级的 mtDNA 分子。此外，降解可能导致可用于 PCR 的片段减少。结果要求在下游基因分型测定之前平行测定线粒体 DNA 的数量和质量。